In the electric circuit breaker art where a bimetallic element is used to flex or bow a given degree in response to passage of electrical current therethrough, a latch of one form or another is provided having a latch member engaging the bimetallic element over a given range of temperatures, and hence currents. Terminal bowing or flexing of the bimetallic element causes disengagement of the latch member to trip the breaker. The bimetallic element or the latch member must be movable with the contacts, the other contact remaining stationary during the contact-breaking process. It is desirable that the tripping temperature or tripping current be established within a fairly close tolerance, therefore a setscrew mechanism is frequently utilized to adjust the position of the latch with respect to the bimetallic element in the unbowed condition, so as to variably adjust the tripping temperature or current. Elimination of such setscrew mechanisms has been a design objective in the electrical circuit breaker art.